1. Field of the Invention
The present invention relates to a shake detection apparatus and shake detection method, and more particularly, to a shake detection apparatus and shake detection method which detect shake by removing a low-frequency component from an output signal of a gyro sensor using a high-pass filter.
2. Description of the Related Art
A mechanism used in an image pickup apparatus such as a camera to compensate for camera shake caused by a photographer is known. Such a camera shake compensation mechanism compensates for shake by detecting angular velocity using a gyro sensor, calculating an amount of shake of the image pickup apparatus from the detected angular velocity, and moving a part of an image pickup unit such as a taking lens or image sensor in a plane perpendicular to a photographic optical axis in such a way as to cancel off the calculated amount of shake. An output signal from a gyro sensor contains unnecessary low-frequency components such as a DC component caused by drift, and thus the low-frequency components are removed by a high-pass filter.
When a camera equipped with a shake compensation mechanism using a gyro sensor and high-pass filter such as described above is panned, swing-back phenomenon occurs at the end of panning, where the swing-back phenomenon is a phenomenon in which even though the camera stops, a screen moves as though the camera were moved in a direction opposite to the preceding shake. The swing-back phenomenon is caused by an overshoot phenomenon of the high-pass filter.
To prevent the swing-back phenomenon, Japanese Patent Application Laid-Open No. 11-284902 describes a technique for shifting cut-off frequency of a high-pass filter to a high-frequency side during panning of a camera. The technique makes it possible to achieve natural camera work without a swing-back phenomenon at the end of panning.